Objective: The objective of this study was to systematically review all literature studying the effect of patient education on patient engagement through patient portals. Introduction: Patient portals provide patients access to health records, lab results, medication refills, educational materials, secure messaging, appointment scheduling, and telehealth visits, allowing patients to take a more active role in their health care decisions and management. A debate remains around whether these additional aids actually improve patient engagement and increase their ability to manage their own health conditions. This systematic review looks specifically at the effect of educational materials included in patient portals. Materials and Methods: In accordance with PRISMA guidelines, the literature search was mapped across 5 databases (PubMed, CINAHL, Scopus, PsychINFO, Embase), and implemented on June 2, 2020. Results: Fifty-two studies were included in the review. Forty-six (88.5%) reported rates of patient utilization of educational resources in the patient portal. Thirty (57.9%) shared patients' perceptions of the usefulness of the education materials. Twenty-one (40.4%) reported changes in health outcomes following educational interventions through the patient portal. This review found that efforts are indeed being made to raise awareness of educational resources in patient portals, that patients are increasingly utilizing these resources, that patients are finding them useful, and that they are improving health outcomes. Conclusion: It seems that patient portals are becoming a powerful tool for patient education and engagement, and show promise as a means of achieving the quadruple aim of healthcare. Moving forward, research should establish more uniform methods of measurement in order to strengthen the literature surrounding the effectiveness of patient education through patient portals.